Spin-Excitation-Instability-Induced Quantum Phase Transitions in Double-Layer Quantum Hall Systems

TL;DR

This paper investigates how spin excitations in double-layer quantum Hall systems can soften, leading to a continuous phase transition to a canted antiferromagnetic state with interlayer spin correlations, using theoretical modeling.

Contribution

It introduces the concept of spin-excitation-induced phase transitions in double-layer quantum Hall systems and characterizes the stability and nature of the resulting canted antiferromagnetic phase.

Findings

Spin density excitations can soften under accessible conditions.

A continuous phase transition to a canted antiferromagnetic phase occurs.

The new phase is energetically stable.

Abstract

We study intersubband spin density collective modes in double-layer quantum Hall systems at $\nu=2$ within the time-dependent Hartree-Fock approximation. We find that these intersubband spin density excitations may soften under experimentally accessible conditions, signaling a phase transition to a new quantum Hall state with interlayer inplane antiferromagnetic spin correlations. We show that this novel canted antiferromagnetic phase is energetically stable and that the phase transition is continuous.